Smoking is a known aetiological risk factor for cervical cancer. Smoking-related DNA damage (DNA adducts), in cervical epithelial cells, has recently been demonstrated to suggest a causal role in the development of cervical cancer. Human papillomavirus 16 (HPV 16) is a known oncogenic virus and is also implicated as a cause of cervical cancer. It has been suggested that both smoking and HPV may act synergistically in the development of cervical cancer. We have investigated the cervical DNA adduct level and the prevalence of HPV 16 (using polymerase chain reaction) in women who had normal cervical cytology. Both the DNA adduct assay and the HPV assay were carried out on exfoliated cervical cells recovered from cervical scrapes. In 87% of the cases there was enough DNA from the exfoliative cervical cells to analyse for DNA adducts. Smokers had higher DNA adduct levels than non-smokers (P = 0.002), confirming the previous data from cervical biopsy samples. Forty-two per cent of the specimens were found to be HPV 16 positive. There was no significant difference in smoking-related DNA damage (DNA adduct levels) between HPV-positive and HPV-negative smokers. This suggests that smoking DNA damage does not augment HPV infectivity. These results do not, therefore, support the molecular synergism theory.